Heretofore, there have been known display apparatus capable of displaying music content, such as musical score display data related to a user-desired music piece. For example, an electronic musical instrument disclosed in Japanese Patent Application Laid-open Publication No. 2007-249033 includes a keyboard, a foot switch, a display screen, an external storage device, a communication interface (I/F), a tone generator circuit, an effect circuit, a sound system, etc., and it can display a musical score in accordance with a musical score data set of a music piece selected through a user's operation. Page turning of the displayed musical score is effected through an operation of a foot switch. Among examples of the musical score display data set, i.e. musical score data set, are ones generated from performance data of a corresponding music piece, ones generated on the basis of musical score logic data of a corresponding music piece read out from a storage device, and ones obtained by reading out, from a storage device, musical score image data themselves of a corresponding music piece.
However, in the prior art technique, musical score data sets are prepared in advance on a per-music-piece basis, and thus, when a user wants to display a musical score of another music piece different from the last one, the user has to perform an operation for selecting the other music piece. Namely, with the prior art technique, the user cannot view musical scores of a plurality of music pieces in a consecutive fashion. Further, in a case where displayable musical score data sets and non-displayable musical score data sets exist in a mixture, the user has to check, when instructing display of a given musical score, whether the given musical score is displayable or not. For example, in a case where the use can display a desired musical score only after the user acquires a corresponding musical score data set as by downloading and carries out a separate procedure for acquiring a license to use the acquired musical score data set, the user cannot display the musical score by merely downloading the musical score data set although the musical score data set is in his or her hand. In another case, an electronic musical instrument may have prestored therein musical score data sets compatible with the musical instrument, but any one of the musical score data sets cannot be displayed before information that the electronic musical instrument is one duly purchased is input (recognized). In such a case, the user can know all of the stored musical score data sets, for example, by displaying a list of the stored musical score data sets, but displayable musical score data sets and non-displayable musical score data sets may exist in the stored musical score data sets.